Apparatus for protecting pipe lines from electrolysis



Aug. 16, 1938.

S. THAYER APPARATUS FOR PROTECTING PIPE LINES FROM ELECTROLYSIS FiledJuly 3, 19s? PHIH Starr Tha er I grvuc wtbt Patented Aug. 16, 1938UNITED STATES PATENT OFFICE APPARATUS FOR PROTECTING PIPE LINES FROMELECTROLYSIS 3 Claims.

it leaves the pipe wall and passes into the surrounding soil, returningto the pipe wall again at some' other spot. These currents may be, andgenerally are, very small, but constant flow over a period of years willeventually cause a breakdown of the pipe wall, necessitating replacementor repair.

It has been discovered heretofore that these currents so generated inthe pipe and between the pipe and surrounding soil, can be preventedfrom leaving the pipe and that corrosion and loss of metal can likewisebe prevented by imposing on the pipe a sufficient potential to overcomethe potential of any currents generated within the pipe and prevent theflow of current from the pipe.

In the actual operation of this method, a source of direct current mustbe available. The negative terminal of this source is attached to thepipe to be protected. The positive terminal is attached to an anodewhich is grounded in the soil at some distance from the pipe. When thecurrent is turned on, it is discharged from the anode into the soil. Itthen passes through the soil and to the pipe wall, from which point itis returned to the source of supply. In order to be effective, thiscurrent must be of sumcient density to counteract the currents that havea tendency to leave the pipe, and if they are of such density, thecorrosion will no longer take place.

In carrying out the foregoing, several means in the past have beenresorted to for the purpose of supplying the necessary direct current tothe location needed. Where a commercial or other power source is alreadypresent in the neighborhood, it is, of course, feasible to tap suchsource and to utilize the current therefrom, using rectifiers, if needbe, in order to transform alternating current of the current supply intothe direct current required for the pipe line protection. In cases whereno source of electric power is available, but where wind power is fairlyconstant, windmills have been set up for the purpose of supplying theneeded electrical energy for pipe line protection purposes. Where thewindmills have not been feasible because of the lack of favorable winds,it has been neces- 5 sary to utilize gas engine driven generators,involving, as they do, the problem of servicing the engine and keepingit in good running order.

It is an object of this invention to provide a method of protecting fuelpipe lines from electrolysis by utilizing a portion of the fuel in thepipe lines.

It is a further-object to provide such a method without any stepsrequiring the exercise of mechanical force.

It is an object of this invention to provide a means for supplyingcurrent for pipe line protection, which means will not require frequentservicing in order to keep it operating.

It is also an object of this invention to provide a device as, above setforth which will be relatively inexpensive to manufacture, to installand operate.

One other object of this invention is to provide a device which willutilize fuel being conducted through a pipe line for the purpose ofsupplying electrical energy to protect the pipe line from corrosion.

With the above and other objects in view, this invention consists of thevarious parts and combinations set forth in the following descriptionand the accompanying drawing and claimed in the appended claims. It isto be understood, however, that said description and drawing are by wayof illustration and example only and are not to be taken by way oflimitation.

In the drawing:

Fig. 1 is a view partly in vertical cross-section illustratingdiagrammatically a device constructed in accordance with this invention.

Fig. 2 is atop plan view of the electrical generator element illustratedin Fig. 1.

Fig. 3 is a plan view of a device such as shown in Fig. 1, butillustrating a number of electrical generator elements connectedtogether in series parallel.

In carrying out this invention a portion of the fuel is drawn from thepipe line, where the same contains fuel, and is burned to produce heat.The heat thus produced is then converted directly into electricity byapplying it to a thermopile, and this electricity is applied to theground at a distance from the pipe line to cause current to flow fromthe ground to the pipe line.

Referring now more in detail to the drawing,

the numeral l illustrates a pipe line which, it will be assumed for thepurposes of this description, is being utilized for theconduction offuel, such as gas or oil. Leading from this pipe line is a supply pipe 2having a valve 3 therein and leading to a burner 3. The burner islocated at the lower end of a flue or oven 5, and extending through thisoven transversely there are disposed a number of thermocouples. Each ofthese thermocouples consists of a length ii of one kind of metal, weldedWithin the oven itself to the end of a length i of a difierent kind ofmetal. These series of thermocouples extending through the oven 5 areconnected, with the thermocouples in series.

It is well known that when a welded joint between two unlike metals isheated and the opposite ends of the metals cooled or kept cooler thanthe welded joints, a current of electricity will be set up by virtue ofthe application of heat to the welded joints. The thermocouplesillustrated in Fig. 1 are connected in series by means of connectors 8so as to form the thermopile illustrated. One end of this thermopile isconnected by means of a conductor 9 to the pipe line I at II), this endbeing the end which is commonly termed the negative end of thethermopile. The conductor I I connects the opposite end to the ground asshown at l2.

It will readily be seen that when the burner l beneath the flue 5 islighted, the heat applied to the welded joints of the thermopile willcause a current flow to be set up in the thermopile, thus applying apotential to the pipe line and preventing the flow of destructiveelectric currents from the pipe line in the manner above described.

In the event it is found that a single thermopile, such as shown in Fig.1, will not supply-the necessary current to prevent the corrosion ofpipe line, additional flues I3, I4 and I5, as many as may be required,may be set up, and thermocouples consis'ting of elements I6 and l1, l8and I9, 20 and 2|, positioned therein in the same manner as the elements6 and l are positioned in the flue 5. The various thermopiles thusprovided may be connected either in series or parallel as shown in Fig.3, depending upon whether more current or more voltage is desired forthe purpose of properly protecting the pipe line.

It will be seen from the foregoing that a means has been provided forcarrying out all of the ,ob-

jects and advantages of this invention. It will further be appreciatedthat while not limited to use on a. pipe line carrying fuel, because thefuel supply may be separately provided, this device is flue surroundingthe portions of said thermopileadapted to be heated, means for supplyingheat to the lower end of said flue below said thermopile, saidthermopile being located adjacent the pipe line and means forelectrically connecting the negative end of said thermopile to said pipeline and the positive end thereof to the ground.

2. Apparatus for protecting buried pipe line against soil corrosion andelectrolysis comprising in combination with the pipe line having fueltherein, burner means connected to said pipe line for burning a portionof the fuel passing therethrough, a flue for receiving heat from saidburner, a plurality of thermocouples extending transversely through saidflue and having their joined ends within said flue, means for connectingsaid thermocouples in series to form a thermopile, said thermopile beinglocated adjacent the pipe line, and means for electrically connectingthe negative end of said thermopile to said pipe line and the positiveend thereof to the ground.

3. Apparatus for protecting buried pipe line against soil corrosion andelectrolysis comprising in combination with the pipe line having fueltherein, burnemneans connected to said pipe line for burning a portionof the fuel passing therethrough, a plurality of flues for receivingheat from said burner meansfa plurality of thermopiles having theirjoints within said fiues, respectively, meansior connecting saidthermopiles in parallel, said thermopiles being located adjacent thepipe line, and means for electrically connecting all of the negativeends of said thermopiles to said pipe line and all of the positive endsthereof to the ground.

STARR THAYER.

